Headlight diffraction-lens



C. G. PETERS.

HEADLIGHT DIFFRACTION LENS mwucmmrs mm) 001. m.

3 2 9 #1 n 2 V 0 N MW H .MW 0% D provements UNITED STATES PATENT OFFICE.

HEADLIGHT DIFIRACTION-LENS.

Specification of Letters Patent.

Patented Nov. 22, 1921.

Application filed October 14, 1920. Serial No. 416,859.

'1 '0 all whom it may concern:

Be it known that I, CHAUNCEY Gr. Pn'rnns, a citizen of the United States, residing at Washington, in the District of Columbia, have invented certain new and useful Imin Headlight Diffractione'nses; and I do hereby declare the'following to be a full, clear, and exact description or" the invention, such as will. enable others skilled in the art to which it appertains to make and use the same.

This invention relates to lamps for vehicles and more particularly to head lights for motor vehicles.

It is well known that glaring lights carried by automobiles is a serious menace to the occupants of vehicles moving in an opposite direction and also to pedestrians on the road over which the vehicle with a glaring light is moving, and the object of my invention is to provide a head light that will not subject the driver of an approaching vehicle to a glaring light, which tends to momentarily blind him, with consequent danger of a collision, and which at the same time will throw a bright light downwardly upon the roadway in front of the vehicle and straight ahead but low down so that the driver may see clearly a sufiicient distance ahead to enable him to steer clear of an approaching vehicle and to avoid obstructions in the road or a ditch in which his machine is liable to be overturned with consequent danger to life and limb of the occupants of the vehicle.

A further object is to provide a simple and inexpensive device of the character referred to, whereby the objectionable features of a glarin light are eliminated without decrease. in light value, or with as little loss of light as possible, and which is adapted to perform the desired functions in consonance with the regulations of diii'erent States or municipalities regarding protective head light lenses. The invention will first be hereinafter more particularly described, with reference to the accompanying drawings, .which form a part of this specification,-and then ointed out in the claims at the end of the escription.

In said drawings,

Figure 1 is a front view of a lens constructed in accordance with my invention;

Fig. 2 is a vertical sectional elevation of a w s d erably in the form of a disk of the desired size and thickness to fit the opening in, or open front of an ordinary parabolic reflector or lamp casin of the construction ordinarily employe in automobile head lights; sald plate having spread over one-half, more or less, of its surface a coat or layer S, of silver or other highly reflecting material, and said coating being overlaid with a protective coating D of lacquer, paint or other material, while the other half or remaining portion of the glass is ruled closely or otherwise formed with fine parallel lines which extend substantially perpendicular to the horizon or the line dividing the silvered and unsilvered portions of the surface, so as to present a series of minute alternating grooves and ridges, that will cause the light to be diffracted and spread the light rays outwardly or laterally over the roadway at either side and in advance of the vehicle. This lens is placed in a suit-able reflector R, or head light casing having a reflecting surface and an open front in which the lens is secured so as to close said opening with the silvered portion of the glass uppermost and on the outer side thereof and the ground or ruled portion below, so that direct and reflected rays of light emanating from an electric lamp or bulb L, will pass out through the lower half or ground portion only of the lens, some rays being projected straight ahead and others downwardly, in the man-.

ner indicated by the arrows in Fig. 3 of the drawings, while the rays of light which are directed upwardly will strike, either directly or by reflection from the upper side of the reflector, that portion of the lens which has a silvered surface and will be reflected backwardlyagainst the upper side of the parabolic reflector, by which they will be reflected downwardly against the lower part of the reflector and thence out through the ground portion of the glass lens, thus cutting ofi the objectionable rays of light and by reflection directing them downwardly and out through the ruled portion of the lens, which spreads or difi'racts the light horizontally, while a beam of light is thrown,

straight ahead, but low down, below the.

plane determined by the locationof the lam I and the line which divides the coated an .rays of. light in' the manner hereinbefore described.

I thus provide an efiicient and inexpensive device adapted to throw a clear light over the roadway in advance of the moving vehicle on which it is carried with: aslittle loss.

of li ht as possible and in a way that ismost helpful to the driver of the vehicle without being objectionable or detrimental. to the driver of an approaching vehicle, and these functions are performed in accordance-with the regulations of different States or =munici- .palities regardingprotective head light lenses.

The lens is preferably circular or disklike in form, and the coating of silver-or equivalent reflecting material preferably c vers one half of the disk on one. side, ,vihile the other half on the same side has a series of lines formed therein, as described, and that portion of the disk on the other side opposite the ruled portion may be ruled to form the desired lines on both sides, if desired. It is also desirable to have the lines which are cut or otherwise formed in linesextendat a slight angle to said dividing ing a glass plate or disk having substantially one half. of the surface thereof on one'side coated with silver or other reflecting mate rial and the remaining portion of said surface ruled to form minute alternating grooves and ridges extending in substantially parallel lines substantially perpendicular to a line dividing said silvered surface from said ruled surface.

3. In combination with a reflector for a vehicle headlight, a lens consisting of a plate or disk of glass having approximately one half of the uppermost portion thereof on one side provided with a coating of silver or equivalent material and the remaining lower portion. of said side ruled to form minute alternating grooves and ridges in substantially parallel lines extending sub stantially perpendicular to the line which.

divides said coating: from. said ruled. lines.

4. A difi'ra'ction lens for a vehicle head light comprising a glass plate having approximately one half of its surface on both.

sides ruled to form minute alternating grooves, and ridges in substantially parallel lines and the other half of one'surface coated with silver or other reflecting material.

In testimony whereof I aflix my signature.

oiiAUNcEY .e. PETERS. 

